Drug profile

The FDA adverse-event record for Unknown Heartworm Prevention

68 adverse-event reports submitted to the FDA Center for Veterinary Medicine reference Unknown Heartworm Prevention. See the species affected, top reactions, and outcomes below.

68
adverse-event reports
0.0%
death-coded share
Dog
most-reported species
47
Lack of efficacy (endoparasite) - heartworm - top reaction
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Important: Adverse event reports do not establish that a drug caused or contributed to the event. Consult your veterinarian before making treatment decisions.
68
Total Reports
0
Deaths Reported
0.0%
Death Rate

Active Ingredients

Unknown Heartworm Prevention

Administration Routes

UnknownOral

Species Affected

Dog 68

Most Affected Breeds

Retriever - Labrador 14
Crossbred Canine/dog 9
Terrier (unspecified) 5
Shepherd Dog - German 3
Chihuahua 2
Coonhound - Black and Tan 2
Beagle 2
Great Pyrenees 2
Dog (unknown) 2
Bulldog 2

Most Reported Reactions

Lack of efficacy (endoparasite) - heartworm 47
Weight gain 3
Lack of efficacy (ectoparasite) - flea 2
Panting 2
Itching 2
Underdose 2
Seizure NOS 2
Shaking 2
Unable to stand 2
Vomiting 2
Lethargy (see also Central nervous system depression in Neurological) 2
Emesis 1

Outcome Breakdown

Outcome Unknown
29 (42.6%)
Ongoing
27 (39.7%)
Recovered/Normal
7 (10.3%)
Recovered with Sequela
5 (7.4%)

Unknown Heartworm Prevention Adverse Event Insights

68 reports name Unknown Heartworm Prevention; 0 recorded a death outcome (0.0% of reported events, not a population-level mortality rate). Active ingredient: Unknown Heartworm Prevention. Administration routes: Unknown, Oral.

By species: Dog (68 reports). By breed: Retriever - Labrador (14), Crossbred Canine/dog (9), Terrier (unspecified) (5).

Leading clinical signs: Lack of efficacy (endoparasite) - heartworm (47), Weight gain (3), Lack of efficacy (ectoparasite) - flea (2), Panting (2). Outcome, 68 coded reports: Outcome Unknown leads at 42.6%.

Read these counts as reporting volume, not risk: per our methodology, a widely-prescribed drug will rack up more raw FDA reports in a given year than a rarely-used one at an identical true rate, so we recommend comparing within similar-exposure products rather than across the full 2025 catalog.

Source: FDA Center for Veterinary Medicine openFDA Animal & Veterinary Adverse Events (CVM AER) · 2025

Every figure on PlainBreed is rendered directly from FDA openFDA adverse event data, no number is typed in by an editor. This page draws directly on FDA openFDA data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.